Macroscopic Friction Coefficient Measurements on Living Endothelial Cells

Dunn, Alison C.; Zaveri, Toral; Keselowsky, Benjamin G.; Sawyer, W. Gregory

doi:10.1007/s11249-007-9230-0

Cited by 58 publications

(51 citation statements)

References 31 publications

(32 reference statements)

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“…The experiments reported here aim to provide insight as to how biological surfaces (cell layers) react to direct contact and sliding against contact lens hydrogel materials. This differs from prior proof-of-concept experiments carried out by Dunn et al [12] with endothelial cells that were tested against glass pins [12], in that the contacting counter material is compliant and hydrated. Under similar loads the contact pressures should be substantially lower, but may not be as low as the forecasted pressures during blinking.…”

Section: Introductionmentioning

confidence: 69%

“…Previously it was reported that there was a threshold normal load of about 0.7 mN above which the endothelial cells would detach [12], presumably, due to the friction forces across this interface. One of the challenges with this work is the difficulty in maintaining low contact pressures on the cell layer; this motivated the use of a compliant hydrogel pin as the countersurface to the cell layer.…”

Section: Discussionmentioning

confidence: 99%

“…The tribology experiments were performed on a dual flexurebased reciprocating pin-on-disk tribometer that is more fully described by Dickrell et al [13,14], Rennie et al [4], Dunn et al [12], and Cobb et al [15]. The contact schematic is shown in Fig.…”

Section: Experimental Protocolmentioning

confidence: 99%

See 2 more Smart Citations

Friction Coefficient Measurement of Hydrogel Materials on Living Epithelial Cells

et al. 2008

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Soft biomaterials are often used in applications that involve contact and relative motion against biological tissues, as well as complicated and variable environments. The friction coefficient of these contacts involving living human cells is of key importance in the analysis and success of these devices. This work measures the contacting friction coefficient between soft hydrogel biomaterial surfaces against live human corneal epithelial cells using a custom micro-tribometer. The friction coefficients were of the order of l = 0.03 for contacts that did not cause gross destruction of the cell layer. Damage to the confluent cell layer was assessed using a Trypan blue stain with optical microscopy. This damage was quantified statistically using image-processing software. The damage was also correlated to in situ friction measurements, with the lowest friction values seen on undamaged cells and higher friction on damaged regions.

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Section: Introductionmentioning

confidence: 69%

Section: Discussionmentioning

confidence: 99%

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Friction Coefficient Measurement of Hydrogel Materials on Living Epithelial Cells

et al. 2008

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“…This co-efficient of friction values for PVA-C was within the range of 0.01-0.05 found by 21,33 and within the arterial values of 0.03-0.06. 8,43 Three sized diameter stenosis of 2, 1.5, and 1 mm corresponding to % area reductions of 56, 75, and 89% respectively were created within the RCA coronary model (Figs. 1e and 1f).…”

Section: Coronary Arteries Phantom Fabricationmentioning

confidence: 99%

The Effects That Cardiac Motion has on Coronary Hemodynamics and Catheter Trackability Forces for the Treatment of Coronary Artery Disease: An In Vitro Assessment

Morris

Fahy

Stefanov

et al. 2015

Cardiovasc Eng Tech

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The coronary arterial tree experiences large displacements due to the contraction and expansion of the cardiac muscle and may influence coronary haemodynamics and stent placement. The accurate measurement of catheter trackability forces within physiological relevant test systems is required for optimum catheter design. The effects of cardiac motion on coronary flowrates, pressure drops, and stent delivery has not been previously experimentally assessed. A cardiac simulator was designed and manufactured which replicates physiological coronary flowrates and cardiac motion within a patient-specific geometry. A motorized delivery system delivered a commercially available coronary stent system and monitored the trackability forces along three phantom patient-specific thin walled compliant coronary vessels supported by a dynamic cardiac phantom model. Pressure drop variation is more sensitive to cardiac motion than outlet flowrates. Maximum pressure drops varied from 7 to 49 mmHg for a stenosis % area reduction of 56 to 90%. There was a strong positive linear correlation of cumulative trackability force with the cumulative curvature. The maximum trackability forces and curvature ranged from 0.24 to 0.87 N and 0.06 to 0.22 mm(-1) respectively for all three vessels. There were maximum and average percentage differences in trackability forces of (23-49%) and (1.9-5.2%) respectively when comparing a static pressure case with the inclusion of pulsatile flow and cardiac motion. Cardiac motion with pulsatile flow significantly altered (p value <0.001) the trackability forces along the delivery pathways with high local percentage variations and pressure drop measurements.

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“…A general contact algorithm was used for all the contact pairs. A friction coefficient of 0.05 was adopted at the tissue-stent interface based on the measurements conducted by Dunn et al [17].…”

Section: Materials Modelsmentioning

confidence: 99%

On the Importance of Modeling Stent Procedure for Predicting Arterial Mechanics

Zhao

Gu²,

Froemming³

2012

Journal of Biomechanical Engineering

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The stent-artery interactions have been increasingly studied using the finite element method for better understanding of the biomechanical environment changes on the artery and its implications. However, the deployment of balloon-expandable stents was generally simplified without considering the balloon-stent interactions, the initial crimping process of the stent, its overexpansion routinely used in the clinical practice, or its recoil process. In this work, the stenting procedure was mimicked by incorporating all the above-mentioned simplifications. The impact of various simplifications on the stentinduced arterial stresses was systematically investigated. The plastic strain history of stent and its resulted geometrical variations, as well as arterial mechanics were quantified and compared. Results showed the model without considering the stent crimping process underestimating the minimum stent diameter by 17.2%, and overestimating the maximum radial recoil by 144%. It was also suggested that overexpansion resulted in a larger stent diameter, but a greater radial recoil ratio and larger intimal area with high stress were also obtained along with the increase in degree of overexpansion.

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Macroscopic Friction Coefficient Measurements on Living Endothelial Cells

Cited by 58 publications

References 31 publications

Friction Coefficient Measurement of Hydrogel Materials on Living Epithelial Cells

Friction Coefficient Measurement of Hydrogel Materials on Living Epithelial Cells

The Effects That Cardiac Motion has on Coronary Hemodynamics and Catheter Trackability Forces for the Treatment of Coronary Artery Disease: An In Vitro Assessment

On the Importance of Modeling Stent Procedure for Predicting Arterial Mechanics

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